[PATCH 0/3] Provide struct ttm_global for TTM global state

[Thomas Zimmermann]

Hi

Am 19.10.18 um 09:24 schrieb Koenig, Christian:
> Hi Thomas,
> 
> I honestly still find that way to complicated compared to what it 
> actually does.
> 
> Both ttm_mem_global and ttm_bo_global can just be some static variables. 
> E.g. the whole handling with drm_global_reference is just superfluous.
> 
> Can I just write a patch to clean up the mess we created?

'Can I?' I don't know :)

Sure, it's a mess. For example, if a driver inits drm_global_reference()
and is later unloaded, there are dangling function pointers to the
driver's code.

I do a slow clean-up of the code because TTM-based drivers depend on the
current way of doing things.

Maybe let me post my full patch set for RFC and discuss this instead.

Best regards
Thomas


> Regards,
> Christian.
> 
> Am 18.10.18 um 18:27 schrieb Thomas Zimmermann:
>> TTM provides global memory and a global BO that is shared by all
>> TTM-based drivers. The data structures are provided by struct drm_global
>> and its helpers. All TTM-based DRM drivers copy the initialization and
>> clean-up code for the global TTM state from each other; leading to code
>> duplication.
>>
>> The new structure struct ttm_global and its helpers provide a unified
>> implementation. Drivers only have to initialize it and forward the
>> contained BO global object to ttm_bo_device_init().
>>
>> The amdgpu and radeon drivers are converted to struct ttm_global as
>> part of this patch set. All other TTM-based drivers share exactly the
>> same code patterns and can be converted in the same way.
>>
>> Future directions: I already have patches for converting the remaining
>> TTM drivers to struct ttm_global. These patches can be merged after
>> the structure has become available in upstream. struct ttm_global is
>> implemented on top of struct drm_global. The latter actually maintains
>> TTM state instead of DRM state. Once all drivers have been converted,
>>      the code for struct drm_global can be merged into struct ttm_global.
>>
>> (Resending this patch set, as I forgot to CC the mailing lists as first.)
>>
>> Thomas Zimmermann (3):
>>    drm/ttm: Provide struct ttm_global for referencing TTM global state
>>    drm/amdgpu: Replace TTM initialization/release with ttm_global
>>    drm/radeon: Replace TTM initialization/release with ttm_global
>>
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 63 ++--------------
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h |  4 +-
>>   drivers/gpu/drm/radeon/radeon.h         |  4 +-
>>   drivers/gpu/drm/radeon/radeon_ttm.c     | 40 ++--------
>>   drivers/gpu/drm/ttm/Makefile            |  2 +-
>>   drivers/gpu/drm/ttm/ttm_global.c        | 98 +++++++++++++++++++++++++
>>   include/drm/drm_global.h                |  8 ++
>>   include/drm/ttm/ttm_global.h            | 79 ++++++++++++++++++++
>>   8 files changed, 200 insertions(+), 98 deletions(-)
>>   create mode 100644 drivers/gpu/drm/ttm/ttm_global.c
>>   create mode 100644 include/drm/ttm/ttm_global.h
>>
>> --
>> 2.19.1
>>
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Linux GmbH, Maxfeldstr. 5, D-90409 Nürnberg
Tel: +49-911-74053-0; Fax: +49-911-7417755;  https://www.suse.com/
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard,
Graham Norton, HRB 21284 (AG Nürnberg)

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